The present invention relates to a safety device for anti-theft mechanisms for motor vehicles.
The prior art shows motor vehicle anti-theft devices intended to lock the steering mechanism of a vehicle when the ignition key is removed or turned to a non-operating position. This type of locking is desirable when the vehicle is at rest. Such anti-theft devices are typically disengaged by inserting a key with the correct "coding" into the ignition lock assembly and rotating the assembly to its start or run position. However, a potential problem with this type of steering lock device is that if a key in a cylinder were to be inadvertently rotated to a non-operating position while the vehicle was in motion the steering mechanism could lock up, thereby preventing a vehicle directional change and resulting in a potential accident. The key could be inadvertently rotated for any number of reasons by an operator or passenger. As a result, the locking of the steering mechanism when a vehicle is in motion should be prevented.
In order to prevent an inadvertent or undesired lock-up of the steering mechanism, devices are known that prevent key removal when the ignition is switched off until a motor vehicle operator performs a specific and independent supplemental operation to rotate the key from its off position to a steering mechanism locked position. Examples of such devices are shown in U.S. Pat. Nos. 3,633,394, 3,789,636 and 4,938,043 wherein an ignition key may be rotated to a lock position from its off position only upon depressing a button adjacent the key.